Location
You can access through this secret mission in Mission 3 at the red door right before the golden statue in the right side of 13th Avenue. In this mission, you are transported back to Love Planet. In there, you are required to kill all of the enemies in 60 seconds.There are Hell Prides, Hell Lusts, and Hell Sloths here.
Walkthrough
For the first timers
You will be experiencing difficulties in passing this mission. You must have Stinger level 2 for this mission. It's just simple; all you need to do is to Stinger every one of them. The Prides will shatter instantly, but the Lust and Sloth won't. So tap the Attack button rapidly to perform Million Stab. If still they won't die either, have a Shotgun and bust them. You have to remember still how to dodge attacks. If the Pride attacks you, side roll, jump or dash. If the Lust attacks you, jump, side roll or dash to the side. If the Sloth teleports, jump.
For experienced fighters
You don't have to worry because you have your own best friend, the Kalina Ann.
For Vergil
Have Stinger Level 2 and Summoned Swords Level 3. Stinger and shoot enemies. If they don't die instantly, perform the Lunar Phase or Helm Breaker. You can also perform a Force Edge combo since it is fast and devastating (but stop the combo right before you open your sword by mashing Style button). If you killed an enemy while performing a combo, quickly Air Trick to the next enemy. If you have Spiral Swords and maxed out DT, perform Spiral Swords and rapidly shoot enemies. You can try out performing shooting and melee attacks together for more devastating damage.